1. Field of the Invention
The present invention relates to a stamp unit provided with a holder which is vertically slidably disposed in a skirt member and retains a stamp material in the lower side and a grip member which is disposed above the holder and moves it downward, and more particularly to a stamp unit capable of readily and surely setting a holder to a predetermined position in a storage part of a stamp manufacturing device for making a stamp from a stamp material held in the holder, and capable of correctly detecting the existence and the type of the holder set to the predetermined position in the storage part.
2. Description of Related Art
Conventionally, the stamp unit of various types has been proposed. Focusing attention on a manufacturing process of a stamp to be used in the stamp unit, one type of the stamp unit is disclosed in Japanese patent application No. Hei 9-249983 which was filed by the present applicant. This stamp unit comprises a grip, a holder, and a skirt member. The holder is connected with the grip so that the holder is vertically movable within the skirt member, and a stamp forming material is disposed in a lower side of the holder.
In the stamp unit, the stamp forming material has a two-layer configuration comprised of an upper layer made of porous hard resin and a lower layer made of porous soft resin in which optical energy absorbing material, such as carbon black, etc., is dispersed. To produce this stamp forming material by means of a stamp manufacturing device, at first, while a part of rolled-up transparent film is drawn out and fed from the roll, characters and figures are printed on the film to form a positive manuscript. This positive manuscript is then brought onto a transparent acrylic plate. Subsequently, the stamp unit integrally constituted of the holder, the grip, and the skirt member is set to a predetermined position in the stamp manufacturing device so that the lower layer of the stamp forming material faces to the manuscript. In such the state, when a xenon tube disposed below the transparent acrylic plate is driven to emit light, the lower layer of the stamp forming material is irradiated with the light through the positive manuscript. The part of the lower layer irradiated with light at sites corresponding to the transparent portion of the manuscript is then fused due to heating effect of the optical absorbing material of the lower layer, and solidified. On the other hand, the part of the lower layer corresponding to the characters and the like on the manuscript is not fused-solidified and remains as it is, thus forming a stamping surface on a lower face of the stamp forming material. To print characters and the like with the stamp unit, the stamping surface of the stamp forming material is applied with ink from the outside such that the ink is saturated into the stamp forming material from the non-fused-solidified portion of the stamping surface, forming characters and the like, and the stamp unit is placed at a desired position on a printing sheet. Upon push of the grip of the stamp unit, the ink saturated in the stamp forming material is caused to ooze through the non-fused-solidified portion onto the printing sheet, and the ink adheres thereto, printing the desired characters and the like.
Meanwhile, the prior art stamp unit is set to a predetermined position in the stamp manufacturing device by engaging a projection formed on the stamp unit with a cutout formed in a stamp making part of the device. For detection of the size of the stamp unit, there is provided a slid volume mounted on an angular C-letter-shaped member in an open/close door. Using the slide volume of which electrical resistance varies as the position of the open/close door, the output of the current from the slide volume is detected, whereby to detect the size of the stamp unit.
The projection of the stamp unit and the cutout of the stamp making part are configured to have less play therebetween and to inherently correspond to each other in shape. To position the stamp unit at a predetermined position by the engagement between the projection and the cutout as mentioned above, the projection has to be properly fitted in the cutout. However, such the proper engagement between the projection and the cutout requires a long time. Unless the proper engagement between the projection and the cutout, the electrical resistance of the slid volume will not correspond to the stamp unit size. Consequently, there may occur a problem of error-detection of the stamp unit size.
To make a lower surface of the stamp forming material disposed below the holder into a stamping surface, the whole stamp unit that is integrally formed of the holder, the grip, and the skirt member is set in the stamp manufacturing device. For this purpose, the stamp manufacturing device needs providing a storage part in which the whole stamp unit can be held and also the space in which other members are to be mounted. Accordingly, the stamp manufacturing device will inevitably become large in size, thereby causing the increase of cost.
For providing a correct and complete stamping surface on a lower surface of the stamp forming material, the stamp unit has to be precisely set to a predetermined position in the stamp manufacturing device. Such the setting of the stamp unit in the stamp manufacturing device requires to provide a projection serving as a positioning mark for the stamp unit. Since the skirt member of the stamp unit is exposed to the outside of the stamp manufacturing device, the positioning projection formed on the skirt member may spoil the appearance of the entire stamp unit, or demerits in design remarkably appear. In this regard, for example, the holder being disposed inside of the skirt member is invisible from the outside, so that there is no problem if the positioning projection serving as a positioning reference or mark is provided to the holder.